In semiconductor testers, it is necessary to transmit a number of signals between signal generating circuits and devices under test (hereinafter, will be referred to as DUTs). Thus transmission lines are formed using relatively thin coaxial cables and strip lines or microstrip lines and the like that are formed with small wiring widths on multilayer wiring boards. On such transmission lines, a large conductor loss or dielectric loss occurs due to skin effect. Further, in actual semiconductor testers, losses are caused by connectors and sockets in addition to losses of transmission lines. Therefore, signal waveforms deteriorate on the ends of DUTs due to these losses. In a known conventional technique for compensating for the deterioration of signal waveforms, including a frequency compensating circuit made up of a resistor and a coil, and a transition signal driving unit made up of a switch, a capacitor, and a current mirror circuit and the like are added to a transmitter driver for transmitting a signal to a transmission line (for example, see patent document 1). By means of the frequency compensating circuit and the transition signal driving unit, peaking current is generated at the rising edge or the falling edge of a transmission signal and the deterioration of a signal waveform on an end of a DUT is prevented.
[Patent document 1] Japanese Patent Laid-Open No. 10-190747 (pp. 2 to 5, FIGS. 1 to 9)